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Publication numberUS2870244 A
Publication typeGrant
Publication dateJan 20, 1959
Filing dateJun 21, 1955
Priority dateJun 21, 1955
Publication numberUS 2870244 A, US 2870244A, US-A-2870244, US2870244 A, US2870244A
InventorsFraser Macintosh Hamish, Jellyman Philip E, Wilcock John E
Original AssigneePilkington Brothers Ltd
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Glass insulator assembly units
US 2870244 A
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)

Jan. 20, 1959 P. E. JELLYMAN ETAL 2,870,244

GLASS INSULATOR ASSEMBLY UNITS Filed June 21, 1955 vPhilip E. Jellyman, Eccleston, St. Helens,

GLASS INSULATOR ASSEMBLY UNITS England,

Hamish Fraser Macintosh, Brora, Sutherland, Scotland, and John E. Wilcock, St. Helens, England, assignors y to Pilkington Brothers Limited, Liverpool, England, a l company of Great Britain Application June 21, 1955, Serial No. 516,948

6 Claims. (Cl. 174-165) in similar manner a mounting pin for the assembly, which pin is shrouded by an externally threaded copper ferrule.

Such an assembly is employed for carrying an electrical power cable, which latter is rested in a recess at the top of the head of the upper shed and is held in situ by a binding wire coiled about the head and about each part of the cable-,adjacent to the head.

The glass sheds are produced by a pressing operation effected in a mould on a charge of molten glass.

The head of the outer shed is usually shrouded by a suitable metal cap to hold it together if it should be fractured. p Y

In :3o-pending application No. 486,962 is described an alternative method of effecting the restricted extraction of heat from the zone prior to chilling the glass to produce a toughened glass shed, this alternative method involving the appliaction of a stream of air to that area in the skirt and near the head intended to form the zone which acts as the barrier in the manner already described.

In the process described in the said co-pending application there is a partial extraction of heat, effected as quickly as possible, from the annular body of glass in the skirt and near the head intended to form the zone, this extraction being effected immediately after the insulator has -been withdrawn from-the temperature equalising furnace by heat exchange with air directed on to the annular body of glass, so that the desired temperature difference between the lglass in the annulus and the ambient glass in" the insulator is obtained, `and immediately a rapid chilling of the outer and inner surfaces of the insulator to toughen the insulator is effected.

In a second co-pending patent application No. 516,992 a further method of protecting the head of an upper shed is described in which the skirt is formed during the pressing operation with a delineated zone which is of somewhat less thickness than the ambient glass, as already described, and then the whole insulator is cooled by simultaneously and symmetrically directing gentle streams of cooling gas, for example air or steam, on to the whole external and internal surface of the insulator after it has left the temperature equalising furnace, so that a slightly toughened product results, that is to say, the degree of toughening obtained'is not such as to produce dicing on a fracture occurring in the glass; but experiments have shown that an insulator thus obtained is approxi- United States Patent O mately three times as strong as an insulator which is completely annealed in the well known manner.

The main object of the present invention is to devise a form of lower shed for insulator assemblies of the kind described which will assist in protecting the head of the upper shed against the effect of the impact of missiles projected from the ground, for example by catapulta against the head when incorporated in a unit assembly.

In accordance with the present invention an insulator assembly unit including a glass insulator (upper shed), a lower shed and a mounting pin is characterised in that the glass insulator comprises a hollow head, a skirt having a radial portion emanating from the base of the head, an annular zone in the radial portion of the skirt, which zone has been thermally treated to prevent the propagation of a fracture initiated in the part of the skirt below the zone, through the zone upwards to the head, and the lower shed comprises a hollow head located within the head of the upper shed and a skirt emanating from the head of the lower shed in downward land outward direction to form an annular ledge below the said annular zone just below the level of the bottom edge of the insulator skirt, and an external annular cavity formed under the said ledge adapted to outwardly deflect missiles projected at the head of the insulator from ground level when the assembly is fixed in operative position.

The part of the skirt of the lower shed forming the wall of the annular cavity may be thermally treated to produce in the wall an annular zone adapted on toughening the insulator to prevent the ,propagation of a fracture in the lower part of the lower shed to the upper part thereof.

The zone in the lower shed may be delineated during the pressing operation, and to this end the wall of the cavity may be formed with an annular zone which is of somewhat less thickness than that of the ambient glass, the upper and under surfaces of the zone being continent with the surfaces of the ambient glass, the zone thus formed being thermally treated as a precedent to toughening the insulator to form the zone into a barrier against the propagation of a fracture in the lower part of the lower shed to the upper part thereof.

ln order that the present invention may be more clearly understood, a preferred embodiment thereof in an assembly unit including an insulator as an upper shed partially toughened as described in the said second copending patent application No. 516,992 will now be described by way of example, with reference to the accompanying diagrammatic drawing which is a central vertical section of the unit.

The glass insulator (upper shed) which is intended to be used for supporting power lines is a pressing'whch comprises a hollow head 1 including a recess 2, for a power line, at the top of the vertical axis 3 3, and an annular shoulder 4 below which is an annular recess 5 adapted to receive the usual binding wire for the line, the pressing also including radially outward (i. e. at right angles from the axis 3 3) from the bottom of the recess 5 a skirt 6, the bead being extended below the top of the skirt to produce the base 7 of the head.

Generally speaking, therefore, the hollow head is of cylindrical form with a recess top and sides, firmly set within the upper part of the skirt, which latter is thickest at the bottom and progressively decreases in thickness towards a zone in the upper part of the skirt as now to be described.

ln the radial portion of the skirt 6 and near to the head 1 an annular zone 8 having a mean width of about half an inch is formed during the pressing operation, which zone is of minimum thickness in the middle, and symmetrically increases in thickness from the middle of the zone, which latter is de'ned by the chain lines 9 9, the upper and under surfaces of the zone being confluent with the surfaces of the ambient glass. The skirt 6 progressively increases in thickness on the outside of the zone towards the rim 1.0 ofthe skirt, and on the inner side towards the base 7 of the heath, the zone 8 having a convex face l1 on the outside and a concave face 12 on the inside.

The interior of the head i in known manner provides a socket 13 with two pockets 14, each extending substantially halfway around. the interior of the head, said socket receiving the hollow head 15 of a glass lower shed comprising a skirt 16. A cementitious lining 17 to the head l. lls the space between the heads l and l5 including the pockets 14 and makes an interlocking joint therebetween. The interior of the head 15 likewise forms a socket for the top of the usual mounting pin llti which is shrouded by an externally threaded copper errule 19, the latter being interlocked with the head 15 by a cementitious lining 2% therein. Thus the pin 18, the lower glass shed Iii-"i6 and the insulator i-G form an integral whole which carries a line indicated at 21 held to the unit assembly by a binding wire 22.

As clearly shown in the drawing, the skirt 16 of the lower shed is flared outwardly immediately from the base of the head J5 and extends outwards practically as far the zone i in the upper shed (as viewed in plan) and forms an annular ledge 23 below the zone and in a plane just below thc level of the bottom edge ot the skirt 6 ot the upper shed.

immediately below the ledge 23 the skirt 16 is formed to define external annular cavity 24 so devised that it hit by a stone, for example catapulted from the ground, the wall of the cavity will deflect the stone from its path of projection outwardly from the assembly or at least so that, if it hits the rim of the skirt 6 below the zone 8 any damage is very much restricted.

The cavity Wall may be thermally treated to produce a zone 25 which then acts as a barrier if the lower shed is fully toughened as fully described in the aforesaid co-pending application 486,962 but the zone may be delineated in the same manner as zone S in the pressing operation by which the lower shed is produced, so that as a result of partially toughening the lower shed in the same manner as the' upper shed, an elective barrier is constivtuted by the zone 2S to the propagation of a fracture through the zone.

ln such arrangement the annular zone 25 is of somewhat less thickness than that of the ambient glass in the insulator.

By the present invention very effective protection is given to the upper shed of the unit assembly against iracture by missiles directed against it from ground level.

By utilizing the constructural forms of insulator sheds irereinbefore described a mechanically sound insulator structure is devised, after the pressed article has been subjected to the usual temperature equalising treatment and then cooled in the manner described, and an insulator of sufficient strength is produced to carry not only the normal load otl the line', but also the seasonal extra loads such as are produced by snow and other condi tions derived from low temperatures.

We claim:

l. An insulator assembly unit comprising a glass insulator', a lower shed and a mounting pin characterised in that the glass insulator comprises a hollow head, a skirt having a radial portion emanating from the base of the bead, an annular zone in the radial portion of the shirt adapted to prevent the propagation of a fracture initiated in the part of the skirt below the zone, through the zone upwards to the head, and the lower shed com pries a hollow head located within the head of the insulator and a skirt emanating radially from the head of ti; lower shed, the upper surface of the skirt emanating in an outward and then downward direction to form firstly an annular ledge positioned beneath the said annular zone at a level just below the level of the bottom edge ot the insulator skirt, and then an external arcuate an nular cavity opening under the said ledge adapted to deiiect outwardly missiles shot at the head of the insulator when the assembly is fixed in position from ground level.

2. An insulator assembly unit according to claim l, wherein the annular zone in the skirt of the glass insulator comprises glass toughencd to a lesser degree than the ambient glass.

3. An insulator assembly unit according to claim l', wherein the annular zone in thc skirt of the glass insulator is of somewhat less thickness than that of the ambient glass, the upper and under surfacesl of the zone being continent with the surfaces of the ambient glass and the whole of the glass insulator being slightly toughened.

4. An insulator assembly unit according to claim l, wherein the wall of the cavity is formed with an annular zone which comprises glass toughened to a lesser degree than the ambient glass.

5. An insulator assembly according to claim l wherein the part of the skirt of the lower shed forming the wall of the annular cavity comprises an annular zone adapted to prevent the propagation of a fracture in the lower part of the lower shed to the upper part thereof.

6. An insulator assembly according to claim l wherein the wall of the cavity is formed with an annular zone which is of somewhat less thickness than that of the ambient glass, the upper and under surfaces of the zone being continent with the surfaces of the ambient glass, and the whole of the lower shed being slightly toughened.

References Cited in the file of this patent UNITED STATES PATENTS 1,192,690 Scbaakc l'uly 25, 1916 .2,162,288 Taylor June 13, 1939 2,418,713 Holmes et al. Apr. 8, 1947 FOREIGN PATENTS 524,663 Great Britain Aug. l2, 1940 UNITED STATES PATENT oEFIcE CERTIFICATE OF CORRECTION Patent No. V2,8"7C5244 January 20, 1959 Philipv ET, Jellymanet al.,

It is hereby certified that error appears inl the above numbered patent requiring correction and that the said vLetters Patent should read as corrected below.

n, between lines 8 and 9 In the heading of the printed specificati@ Great Britain July 26, M954 o thereof, insert Claims priority, application Signed and sealed this 30th day of June 1959.

C .(sE-AL) Attest: i

KARLH- AXLIN ROBERT c. wATsoN Attesbng'lofflcer Commissioner of Patents UNITED STATES PATENT oEFIcE CERTIFICATE OF CORRECTION Patent No. V2,8"7C5244 January 20, 1959 Philipv ET, Jellymanet al.,

It is hereby certified that error appears inl the above numbered patent requiring correction and that the said vLetters Patent should read as corrected below.

n, between lines 8 and 9 In the heading of the printed specificati@ Great Britain July 26, M954 o thereof, insert Claims priority, application Signed and sealed this 30th day of June 1959.

C .(sE-AL) Attest: i

KARLH- AXLIN ROBERT c. wATsoN Attesbng'lofflcer Commissioner of Patents UNITED STATES PATENT OFFICE -1- CERTTFICATE 0F CORRECTION January 20, 1959 Patent No. 2,870,244

Philip'Ea Jellyman et al It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

In the heading of the printed specification, between lines 8 and 9 thereof, insert Claims priority, application Great Britain July 26, 1954 w Signed-and sealed this 30th day of June i959n .(SEAL) Attest: i

KARLH- AXLINE l p ROBERT c. wATsoVN, l Conmissoner of Patents ttesting-Oificer

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US1192690 *Jun 5, 1913Jul 25, 1916Westinghouse Electric & Mfg CoInsulator-supporting structure.
US2162288 *Mar 9, 1938Jun 13, 1939Taylor John JInsulator
US2418713 *Sep 14, 1944Apr 8, 1947Owens Illinois Glass CoThermally toughened insulator
GB524663A * Title not available
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3141063 *Jan 4, 1961Jul 14, 1964Pilkington Brothers LtdToughened glass, pin type insulator
US5413443 *Sep 22, 1993May 9, 1995Joslyn Manufacturing Co.Method and apparatus for mounting an insulator thread onto a pin of a power line
Classifications
U.S. Classification174/165, 174/195, 174/188
International ClassificationH01B17/00, H01B17/20
Cooperative ClassificationH01B17/20
European ClassificationH01B17/20